Very high rotational frequencies and band termination in Br-73 - art. no. 014313

Rotational bands in Br-73 have been investigated up to spins of I = 65/2 us ing the EUROBALL III spectrometer. One of the negative-parity bands display s the highest rotational frequency (h) over bar omega = 1.85 MeV reported t o date in nuclei with A greater than or equal to 25. At high frequencies, t he experimental J((2)) dynamic moment of inertia for all bands decreases to very low values, J((2))less than or equal to 10 (h) over bar(2) MeV-1. The bands are described in the configuration-dependent cranked Nilsson-Strutin sky model. The calculations indicate that one of the negative-parity bands is observed up to its terminating single-particle state at spin 63/2. This result establishes the first band termination in the A approximate to 70 ma ss region.